Switchable diffuser projection systems and methods

ABSTRACT

A system including: a light source, a switchable diffuser, a structured light detector, and a ToF detector. The light source and switchable diffuser are controlled to operate in concert (together, and/or with other optical and electrical elements of the system) to project pulses of collimated beams of light (interleaved between pulses of flood light) during a single image capture period, the pulses of collimated beams of light being resolvable by the structured light detector and the ToF detector within the same image capture period.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of U.S.Non-provisional patent application Ser. No. 16/259,812, filed on Jan.28, 2019 and entitled “SWITCHABLE DIFFUSER PROJECTION SYSTEMS ANDMETHODS”, which is based on and claims priority to Chinese PatentApplication No. 201910035662.5, filed on Jan. 15, 2019. The presentapplication is also based on and claims priority to Chinese PatentApplication No. 201910073808.5, filed on Jan. 25, 2019. Theabove-referenced applications are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

This disclosure relates to systems and methods projecting light, andselectively controlling the projection of such light using a switchablediffuser arrangement.

BACKGROUND

Light projecting technologies are essential for enabling severalimportant device functionalities. For example, structured lightprojecting is deployed in 3D camera modules of mobile phones forrecognizing facial features. The projected light reflects off the facialfeatures can be captured by a detector and analyzed by algorithms to“perceive” the topology of the face. Accordingly, authentication, emojigeneration, image capture orientation, and other various functionalitiescan be designed based on inputs of the facial feature recognition.

Current light projecting technologies are disadvantaged for high cost,large size, and low integration. In particular, conventional lightprojecting technologies do not fully utilize already available lightsources to achieve the multiple functions sought, and instead utilizemultiple projection means to achieve their objectives. Theseinefficiencies impose bottlenecks for the advancement of devicestructure and function built on or around the light projection features.Therefore, improvements over the existing light projecting technologiesare desirable for both the consumer market and the industry.

Light projection is a key step for various applications such as 3Dfeature detection and 3D mapping. In conventional systems, multiplelight sources and light projection subsystems are deployed incombination with one another to provide 3D feature detection and 3Dmapping technology. For instance, many conventional systems mount both adistinct flood light illumination component and a distinct dot projectorcomponent to achieve the desired readings. In general, the lightproduced by the flood light component is broad beam light that spreadssubstantially as it propagates. Flood light is used to illuminate asurface of interest for image capture. The light produced by dotprojector, on the other hand, is narrow beam light configured withsubstantially parallel rays that do not disperse or diverge withpropagation as readily as flood light. Using two distinct light sourcesto achieve both flood light illumination and dot projection isinefficient and results in cumbersome modules that are ill suited forsmall environments.

SUMMARY

Various embodiments of the present disclosure include light projectingsystems and structures, switchable diffusers and other devices.

According to one aspect, a light projecting system comprises: a lightprojecting system configured to project a plurality of collimated beamsof light; a switchable diffuser having a first surface and a secondsurface, the switchable diffuser coupled to a control source andconfigured to change from a first state to a second state responsive tothe control source being changed from a first condition to a secondcondition; wherein in the first state the switchable diffuser isconfigured to receive at least a portion of the plurality of collimatedbeams of light at the first surface and project a flood light out of thesecond surface; wherein in the second state the switchable diffuser isconfigured to permit at least a portion of the plurality of collimatedbeams of light to propagate out of the second surface as an array; and aprocessing engine electrically coupled with a non-transitory computerreadable medium having machine readable instructions stored thereon,which, when executed by the processing engine, cause the system to:oscillate the control source between the first condition and the secondcondition in accordance with a first predetermined pattern. It will beunderstood that, for purposes of this disclosure, the term “computerreadable medium” extends to any medium configured to store machinereadable instructions that can be executed by a processing engine. Forexample, such mediums may be found in a microcontroller unit, as systemon a chip, or in any combination of the foregoing.

In some embodiments, the light projecting system comprises avertical-cavity surface-emitting laser (VCSEL) element, a diffractionoptics element, and/or a waveguide.

In some embodiments, the light projecting system comprises a waveguide,the waveguide comprising a surface A and a surface B; the surface Acomprises a plurality of grating structures; the waveguide is configuredto guide an in-coupled light beam to undergo total internal reflectionbetween the surface A and the surface B; and the grating structures areconfigured to disrupt the total internal reflection to cause at least aportion of the in-coupled light beam to couple out of the waveguide fromthe surface A, the portion of the in-coupled light beam coupled out ofthe waveguide forming out-coupled light beams comprising the pluralityof collimated beams of light; the surface A is in an x-y planecomprising an x-direction and a y-direction perpendicular to each other;the in-coupled light beam propagates inside the waveguide substantiallyalong the x-direction of the x-y plane; the out-coupled light beamspropagate substantially along a z-direction normal to the x-y plane; thegrating structure is each associated with a grating depth, a duty cycle,a period, and an orientation in the x-y plane with respect to thez-direction; the grating structures at different x-direction positionshave at least one of different grating depths or different grating dutycycles; the grating structures at different x-direction positions havedifferent periods; and the grating structures at different y-directionpositions have different orientations.

In some embodiments, the light projecting system comprises a pluralityof diodes.

In some embodiments, the system further comprises: a detector configuredto capture light information based on one or more flood lightreflections off of an object, and array reflections off of an object,wherein: the machine readable instructions, when executed by theprocessing engine, cause the system to demultiplex light informationreceived at the detector.

In some embodiments, the switchable diffuser comprises a polymer-liquidcrystal mixture having a molecular orientation responsive to an appliedvoltage.

In some embodiments, the switchable diffuser comprises a polymerdispersed liquid crystal.

In some embodiments, the switchable diffuser comprises a polymer networkliquid crystal.

In some embodiments, the first predetermined pattern causes the lightprojecting out of the second surface of the switchable diffuser tocomprise alternating bursts of flood light and collimated beams of lightachieving a time division multiplexed emission.

In some embodiments, the first voltage condition is an applied voltageof 0V, and the second voltage condition is an applied voltage of between1 V and 50 V or more.

In some embodiments, the first predetermined pattern comprises switchingbetween the first voltage condition and the second voltage condition twoor more times during image capture period to achieve a predeterminedratio of flood light projection to collimated light projection.

In some embodiments, the predetermined oscillation pattern is configuredto achieve a predetermined projection ratio of flood light to collimatedlight.

In some embodiments, the predetermined oscillation pattern is configuredto achieve a predetermined projection ratio of flood light to collimatedlight, and the projection ratio is 1:1.

In some embodiments, the predetermined oscillation pattern is configuredto achieve a predetermined projection ratio of flood light to collimatedlight, and the projection ratio is 10:1.

In some embodiments, the predetermined oscillation pattern is configuredto achieve a predetermined projection ratio of flood light projectiontime to collimated light projection time, and the projection ratio isabout between 1:1 to 10:1.

In embodiments, the non-transitory computer readable medium is furtherconfigured with machine readable instructions stored thereon, which,when executed by the processing engine, cause the system to: oscillatethe control source between the first condition and the second conditionin accordance with a second predetermined pattern; and the secondpredetermined pattern comprises switching between the first voltagecondition and the second voltage condition two or more times during asecond image capture period to achieve a second predetermined ratio offlood light projection to collimated light projection, and furtherwherein the second predetermined ratio is different than the firstpredetermined ratio.

In some embodiments, the non-transitory computer readable medium isfurther configured with machine readable instructions stored thereon,which, when executed by the processing engine, cause the system to:adjust the time period of one or more of the first image capture periodand the second image capture period based on one or more of a detectedambient lighting condition and a transaction security condition.

According to another aspect, a light projecting method comprises:projecting a plurality of collimated beams of light; providing aswitchable diffuser having a first surface and a second surface, theswitchable diffuser coupled to a control source and configured to changefrom a first state to a second state responsive to the control sourcebeing changed from a first condition to a second condition; wherein inthe first state the switchable diffuser is configured to receive atleast a portion of the plurality of collimated beams of light at thefirst surface, and project a flood light out of the second surface;wherein in the second state the switchable diffuser is configured topermit at least a portion of collimated beams of light to propagate outof the second surface as an array; oscillating the control sourcebetween the first condition and the second condition in accordance witha first predetermined pattern.

In some embodiments, projecting the plurality of collimated beams oflight comprises projecting the plurality of collimated beams of lightfrom a waveguide, the waveguide comprising a surface A and a surface B;the surface A comprises a plurality of grating structures; the waveguideis configured to guide an in-coupled light beam to undergo totalinternal reflection between the surface A and the surface B; and thegrating structures are configured to disrupt the total internalreflection to cause at least a portion of the in-coupled light beam tocouple out of the waveguide from the surface A, the portion of thein-coupled light beam coupled out of the waveguide forming out-coupledlight beams comprising the plurality of collimated beams of light.

According to another aspect, a system in accordance with the presentdisclosure includes: a light source configured to generate light (e.g.,IR light); a projecting structure configured to receive the generatedlight and responsively project a plurality of collimated beams of light(collectively referred to herein as a light projecting structure); and aswitchable diffuser having a first surface and a second surface. In someembodiments, the switchable diffuser is coupled to a control source suchas a voltage source. Though other control sources may be implementedwith the present technology (e.g., current sources, etc.), the presentdisclosure regularly refers to a voltage sources by way of example only,and are not intended to be limiting. The switchable diffuser isconfigured to change from a first state to a second state responsive tothe voltage source being changed from a first voltage condition (e.g.,0V) to a second voltage condition (e.g., 1-50V). When the switchablediffuser is in the first state, the switchable diffuser is configured toreceive the plurality of columnated beams of light at the first surface,diffuse the plurality of collimated beams of light and project a floodlight out of the second surface. When the switchable diffuser is in thesecond state, the switchable diffuser is configured to be substantiallytransparent to the plurality of collimated beams of light incident uponit, and to permit the plurality of collimated beams of light topropagate out of the second surface as an array (e.g., a dot array).Example systems may also include a detector configured to capture lightinformation based on one or more flood light reflections off of anobject, and dot array reflections off of an object. In some embodiments,the system is configured to demultiplex light information received atthe detector.

In some embodiments, an example system of the present disclosure isprovided with a controller to manipulate and regulate operations ofelements of the system. The controller may include a processing engineelectrically coupled with a non-transitory computer readable mediumhaving machine readable instructions stored thereon, which, whenexecuted by the processing engine, cause the system to perform variousoperations. For example, in some instances the instructions, whenexecuted, cause the system to oscillate the voltage source between thefirst voltage condition and the second voltage condition in accordancewith a predetermined oscillation pattern. In some embodiments, thepredetermined oscillation pattern causes the light projecting out of thesecond surface of the switchable diffuser to comprise alternating burstsof flood light and collimated beams of light achieving a time divisionmultiplexed emission. In some embodiments, the predetermined oscillationpattern comprises switching between the first voltage condition and thesecond voltage condition two or more times during image capture periodto achieve a predetermined ratio of flood light projection to collimatedlight projection (e.g., from anywhere between 1:1-10:1, 1:1-100:1,1:10-1:1, or 1:100-1:1, etc.).

In some embodiments, the systems of the present disclosure may include amodule equipped with both a structured light detector (i.e., a non-ToFdetector, e.g., an IR dot array detector) as well as a Time-of-Flight(“ToF”) detector. Both of the structured light detector and the ToFdetector may be configured to receive light reflections from the lightpulses projected from light projection system, but each may capture,transduce, filter, and/or assess the light differently (or producesignals that may be filtered and/or assessed differently) to derivefeature, structure and/or depth information about objects upon which thelight projected from light projecting system is incident.

In some embodiments, a light projecting subsystem of a system includingboth a structured light detector and a ToF detector may neverthelessinclude a single light source and single switchable diffuser. Such lightsource and switchable diffuser may operate in accordance with one ormore features of such elements as discussed herein. In some embodiments,systems of the present disclosure may include a controller coupled withthe structured light detector and the ToF detector, and configured tooperate only one of the structured light detector and the ToF detectorduring a given image capture period—e.g., in “ToF mode” or “non-ToFmode” (ToF mode referring to the situation where only a ToF detector isoperating during a given image capture period, and “non-ToF mode”referring to the situation where only a structured light detector isoperating during a given image capture period. In other embodiments,such a controller may be configured to operate both the structured lightdetector and the ToF detector together during a given image captureperiod—e.g., in “hybrid mode” (hybrid mode referring to the case wherecontroller synchronizes operations of the structured light detector andthe ToF detector (along with the operation of other elements of thesystem, e.g., the timing of the switchable diffuser's change of state,the timing of the light sources emissions within the light projectingsubsystem of the system, etc.) such that both detectors may coherentlyoperate during a given image capture period.

In some embodiments employing ToF detectors, controller may switchbetween modes—e.g., switch between operation of the system in ToF mode,non-ToF mode, or hybrid mode—based on input from a user (e.g., userselection), or based upon one or more detected condition(s) (e.g.,lighting conditions, component status detection, etc.).

In some embodiments, the technology of the present disclosure mayinclude a system, comprising: an IR detector configured to capture lightinformation based on one or more flood light reflections off of anobject, and structured light array reflections off of an object; aTime-of-Flight (ToF) detector configured to measure time differencesbetween the returning light reflections off of a surface of the object(or off of multiple surfaces of different objects), and to enable thedetermination of one or more depth measures associated with differentportions of such surface(s) based on the time differences betweendifferent portions of returning light reflections; and a switchablediffuser having a first surface and a second surface, the switchablediffuser coupled to a control source and configured to change from afirst state to a second state responsive to the control source beingchanged from a first condition to a second condition. In some suchembodiments the first state the switchable diffuser may be configured toreceive at least a portion of the plurality of collimated beams of lightat the first surface and project a flood light out of the secondsurface. In second state the switchable diffuser may be configured topermit at least a portion of the plurality of collimated beams of lightto propagate out of the second surface as an array. In some embodiments,the light projecting system includes a processing engine electricallycoupled with a non-transitory computer readable medium having machinereadable instructions stored thereon, which, when executed by theprocessing engine, cause the system to: oscillate the control sourcebetween the first condition and the second condition in accordance witha first predetermined pattern. In some embodiments, oscillating thecontrol source between the first condition and the second condition inaccordance with a first predetermined pattern causes a plurality ofpulses of collimated light to be projected out of the switchablediffuser during a single image capture period. In some embodiments, theToF sensor and the structured light sensor are configured to receivereflections of collimated light from one or more of the same pulses ofcollimated light during a single image capture period.

In some embodiments, the switchable diffuser may be controlled to emitpulses of collimated beams of light that effectuate a modulation of thecollimated beams of light that the ToF detector may be configured toresolve. Such modulation may be one or more of pulsed amplitudemodulation, pulsed frequency modulation, continuous wave amplitudemodulation, and continuous wave frequency modulation.

In some embodiments, the technology provided herein is drawn to methodsfor performing the functionality described with respect to the examplesystems hereof.

According to another aspect, a light projecting system comprises: an IRdetector configured to capture light information based on one or moreflood light reflections off of an object, and array reflections off ofan object; a Time-of-Flight (ToF) detector configured to detectdifferences between particles based on their time of flight; aswitchable diffuser having a first surface and a second surface, theswitchable diffuser coupled to a control source and configured to changefrom a first state to a second state responsive to the control sourcebeing changed from a first condition to a second condition; wherein inthe first state the switchable diffuser is configured to receive atleast a portion of the plurality of collimated beams of light at thefirst surface and project a flood light out of the second surface;wherein in the second state the switchable diffuser is configured topermit at least a portion of the plurality of collimated beams of lightto propagate out of the second surface as an array; and a processingengine electrically coupled with a non-transitory computer readablemedium having machine readable instructions stored thereon, which, whenexecuted by the processing engine, cause the system to: oscillate thecontrol source between the first condition and the second condition inaccordance with a first predetermined pattern; cause the switchablediffuser to emit pulses of collimated beams of light to effectuate amodulation of the collimated beams of light that the ToF detector isconfigured to resolve.

According to another aspect, a light projecting method comprises:receiving light generated by a light source light and responsivelyprojecting a plurality of collimated beams of light; providing aswitchable diffuser having a first surface and a second surface, theswitchable diffuser coupled to a voltage source and configured to changefrom a first state to a second state responsive to the voltage sourcebeing changed from a first condition to a second condition; andoscillating the voltage source between the first condition and thesecond condition in accordance with a first predetermined pattern, thevoltage oscillations causing alternating flood light and dot arrayprojections to be emitted from the second surface of the switchablediffuser in a time-division multiplexed manner.

In some embodiments, the method further comprises detecting, at a lightsensor, light information from the alternating flood light and dot arraylight reflections off of an object, wherein the light sensor issynchronized with the voltage oscillations and/or the alternations inflood light and dot array light projection; demultiplexing lightinformation detected at the light sensor; and generating a 3D map of theobject based on the demultiplexed light information.

These and other features of the systems, methods, and non-transitorycomputer readable media disclosed herein, as well as the methods ofoperation and functions of the related elements of structure and thecombination of parts and economies of manufacture, will become moreapparent upon consideration of the following description and theappended claims with reference to the accompanying drawings, all ofwhich form a part of this specification, wherein like reference numeralsdesignate corresponding parts in the various figures. It is to beexpressly understood, however, that the drawings are for purposes ofillustration and description only and are not intended as a definitionof the limits of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain features of various embodiments of the present technology areset forth with particularity in the appended claims. A betterunderstanding of the features and advantages of the technology will beobtained by reference to the following detailed description that setsforth illustrative embodiments, in which the principles of the inventionare utilized, and the accompanying drawings of which:

FIG. 1 is a graphical illustration of an example system in accordancewith various embodiments of the present disclosure.

FIG. 2 is a side-view graphical illustration of an exemplary system forprojecting flood light and dot light in a time-division multiplexedmanner using a single light source and a switchable diffuser inaccordance with various embodiments of the present disclosure.

FIG. 3A illustrates a change in the operation of an example switchablediffuser, in a first position within an example system arrangement, upona change in an applied electric field across the switchable diffusercaused by a switch from a first voltage condition to a second voltagecondition, in accordance with one or more embodiments of the presentdisclosure.

FIG. 3B illustrates a change in the operation of an example switchablediffuser, in a second position within an example system arrangement,upon a change in an applied electric field across the switchablediffuser caused by a switch from a first voltage condition to a secondvoltage condition, in accordance with one or more embodiments of thepresent disclosure.

FIG. 3C illustrates a change in the operation of an example switchablediffuser, in a third position within an example system arrangement, upona change in an applied electric field across the switchable diffusercaused by a switch from a first voltage condition to a second voltagecondition, in accordance with one or more embodiments of the presentdisclosure.

FIG. 4 illustrates an example architecture depicting varioussubcomponents of a controller that may be implemented in accordance withvarious embodiments of the present disclosure.

FIG. 5 is a graphical illustration of another example system inaccordance with various embodiments of the present disclosure, includinga module combining a Time of Flight (ToF) detector with an IR detectorand a switchable diffuser.

FIG. 6 is a process flow chart illustrating an example method that maybe implemented in accordance with one or more embodiments of the presentdisclosure.

The figures are not intended to be exhaustive or to limit the inventionto the precise form disclosed. It should be understood that theinvention can be practiced with modification and alteration, and thatthe disclosed technology be limited only by the claims and theequivalents thereof.

DETAILED DESCRIPTION

The disclosure and figures of each of U.S. application Ser. Nos.16/036,776, 16/036,801, and 16/036,814 are hereby incorporated byreference into the instant disclosure in their entirety. Similarfeatures and elements within each specification may be substituted orreapplied for one or more elements discussed below, as will be readilyapparent to a person of ordinary skill in the art.

FIG. 1 illustrates a diagram depicting an example system for achieving3D feature detection in accordance with one or more embodiments of thepresent disclosure. Referring to FIG. 1, a system 100 for achieving 3Dfeature detection may include a light projecting subsystem 130 and adetector 120 mounted to a module 110 (the module providing structural,optical, and/or electrical support), and a controller 140 in operativecommunication with module 110 (or one or more elements of module 110).As discussed in more detail herein, light projecting subsystem 130 maybe configured to selectively produce both flood light and dot lightprojections during image capture, avoiding the need to mount and usemultiple distinct light projection systems within a given module. System100 may be implemented in various systems or devices, such as mobilephones, computers, pads, wearable devices, vehicles, etc.

Light projecting subsystem 130 may comprise various elements, includingone or more light sources (e.g., a component of a light projectingsystem 130), shown with more particularity in FIG. 2-5. A light sourceof such a light projecting subsystem 130 may project structured orcolumnated light beams of a predetermined or random pattern onto asurface. The structured or columnated light may be coupled into andthrough one or more other optical and optoelectronic elements of thelight projecting subsystem 130, such as a lens and/or switchablediffuser element. In operation, light emitted out of such a switchablediffuser element may be directed toward a surface of an object ofinterest (e.g., such as a face). Reflections of light off of the surfacean object may be captured by one or more detectors 120 (e.g., camerasensors). Light information captured by detectors 120 may be used todetermine depth information (in the case of reflected columnated light,based on shifts and distortions relative to a reference) and objectfeature information (in the case of reflected flood light, based onwavelength/frequency). Various other optically derived parameters may bedetermined based on the reflected light as captured by the detectors120. In some embodiments, the detector is configured to receivereflections of out-coupled beams off multiple locations on a distantobject to determine distances of the multiple locations relative to thesystem, or a designated element of the system, or a designated referencepoint in relation to the system.

As shown, the light projecting subsystem 130 and detector 120 may bemounted to or otherwise coupled with the same modular structure (e.g.,module 110). In some embodiments, the light projecting subsystem 130 anddetector 120 are mounted to or otherwise coupled with different modules.In each case, however, detector 120 may be positioned to assume anorientation relative to the light projecting subsystem 130 such thatreflections of the projecting subsystem's light off of multiplelocations on a distant object may be received by the light sensors ofthe detector elements. The received reflections may be used to determinedistances of the multiple locations relative to a predeterminedreference point (e.g., the position of the light projecting subsystem130). In some embodiments, a virtual flat reflective plane at a singleposition on the surface of the object may be used as a reference, andreflections of the projected light off the reference can bepredetermined as reference reflection beams. A surface topology (e.g.,facial features in the case of a facial surface) can be determined basedon the differences between the detected reflection beams and thereference reflection beams, manifested as shifts or distortions of thereference reflection beams. Such determination method may be known asthe triangulation method.

FIG. 2 is a side-view graphical assembly illustration of an examplesystem 100 for projecting both flood light and dot light projectionsfrom a light projection subsystem to achieve 3D feature detection inaccordance with one or more embodiments of the present disclosure inaccordance light in accordance with various embodiments of the presentdisclosure. Referring to FIG. 2, an example light projecting subsystem130 (introduced in FIG. 1) may include a light source 132, a lightprojecting structure 134, and a switchable diffuser 136. An examplelight projecting structure 134 may be a beam array projecting structure,such that the projected beam array forms an array (e.g. a dot array) ona surface (e.g., a 2D surface, a 3D surface, etc.). In operation, thelight from the light source passes through the light projectingstructure 134 and the switchable diffuser 136 to reach the object (notshown) of interest for imaging. Detector 120 (introduced in FIG. 1) mayinclude a light sensor 122 configured to receive and process the lightreflected off of the object being imaged. Detector 120 may in someinstances include one or more other optical or optoelectronic elementsto filter, channel or otherwise guide desirable light reflections tolight sensor 122. Filter 124 is shown in FIG. 2 is an example of anoptical element that may be used in connection with light sensor 122.

Light source 132 may comprise any form of light source. For example,light source 132 may emit infrared (IR) light, or any other visible ornonvisible light within any range of the electromagnetic spectrum. Forexample, light source 132 may include a single laser (e.g., anedge-emitting laser, a vertical-cavity surface-emitting laser (VCSEL)),a light-emitting diode (LED) with light collimation, or the like.Alternatively, the light source 132 may comprise multiple lasers ordiodes (e.g., an edge-emitting laser array, a VCSEL array, a LED array).The light source 132 may include one or more of the light sourcesdisclosed in U.S. application Ser. Nos. 16/036,776, 16/036,801, and16/036,814, each of which is incorporated herein by reference in itsentirety.

Light projecting structure 134 may comprise a waveguide configured toreceive light emitted from light source 132, and project a plurality ofdot beams. In such embodiments, light from light source 132 may coupleinto light projecting structure 134 from any surface or portion of asurface, and/or couple out of the light projecting structure 134 fromany surface or portion of a surface.

Light projecting system 130 may comprise any one or more of the lightprojecting devices and light projecting structures disclosed in U.S.application Ser. Nos. 16/036,776, 16/036,801, and 16/036,814, each ofwhich is which is incorporated herein by reference in its entirety. Inone nonlimiting example, in some embodiments, the light projectingsystem 130 may comprise a projection lens structure such as projectionlens structure 231 of U.S. application Ser. No. 16/036,801, which may beconfigured to collimate the light from the light source, and/or toproject a random or structured dot array. For example, per workingdistance requirement of different applications, the laser waist of theprojected beam array as collimated by the projection lens structure 231can vary from 10 mm to 1 meter. Thus, the projection lens structure 231may collimate the output light to form clear image (e.g., a dot array)at a distance of interest (e.g., in the range of 10 cm to 10 m dependingon the application). In another nonlimiting example, any of the gratingstructures disclosed in U.S. application Ser. No. 16/036,801 may beutilized as, with, or in connection with one or more of the lightsources 132, projection lenses, and/or waveguides 134 introduced in thepresent disclosure. In another nonlimiting example, light projectingsubsystem 130 may comprise the system 102 of U.S. application Ser. No.16/036,801.

In some alternative embodiments, light projecting subsystem 130 maycomprise multiple diodes (e.g., lasers such as an edge-emitting laserarray or a VCSEL array, diodes such as a LED array), or any otherstructure that produces a beam array arranged to impinge on at least aportion of the switchable diffuser material. Light projecting subsystem130 may include one or more of the structures or systems disclosed inU.S. application Ser. Nos. 16/036,776, 16/036,801, and 16/036,814, eachof which is incorporated herein by reference in its entirety.

In some alternative embodiments, light projecting subsystem 130 maycomprise a diffraction optical element (“DOE”) to generate multiple dotsin combination with a VCSEL array. For example, if the VCSEL arraycomprises 150 dots (e.g., beams of collimated light), the DOE incombination therewith may effectively provide a 10× multiplier togenerate 1500 dots at the output plane. In another example, if the VCSELarray comprises 300 dots (e.g., beams of collimated light), the DOE incombination therewith may effectively provide a 100× multiplier togenerate 30000 dots at the output plane. Any type of DOE may beemployed, including DOEs that generate any multiple of dots as theunderlying VCSEL array (e.g., 10×-100×, or greater or less).

In some embodiments, light beams emerging from the light projectingstructure 134 may couple out from a surface of the light projectingstructure 134. Then, optionally, the light beams may pass through theswitchable diffuser 136 to be projected into the space. The switchablediffuser 136 may be configured to receive beams from the light source132 and project the beams (in the same or modified form) into anenvironment containing a distant object to be imaged. Alternatively, thelight beams may be directly projected from the light source 132 intoswitchable diffuser 136, and the into the space. In some embodimentswhere a light projecting structure 134 is utilized (as shown in thefigures), the light projecting structure 134 may comprise various lensor lens combinations (e.g., one to six pieces of separate lenses) forcontrolling directions of the projected beams.

Switchable diffuser 136 may comprise any liquid crystal or polymer basedmixture having an adjustable molecular orientation responsive to anapplied voltage, including, for example, any prior art mixtures. Forexample, switchable diffuser 136 may include any a polymer-liquidcrystal mixture, or any other liquid crystal mixture. In someembodiments, the switchable diffuser 136 may comprise an immisciblemixture of liquid crystal and polymer such as a polymer dispersed liquidcrystal (PDLC), or a polymer network liquid crystal (PNLC), or DLPmaterial. Such mixtures combine the electro-optical properties of liquidcrystals with structural properties provided by polymers.

In some embodiments, the switchable diffuser 136 may display opticalscattering properties when it is not subjected to a substantial electricfield. PDLC type switchable diffusers 136, for instance, may providesuch optically scattering properties. In some embodiments of a PDLC typeswitchable diffuser 136, the concentration of polymer within the liquidcrystal may be about between 20% to 60% to achieve scattering. In someembodiments of a PDLC type switchable diffuser 136, the concentration ofpolymer within the liquid crystal may be about between 60% to 80%. Thepolymer is cured within the liquid/polymer emulsion such that dropletsof liquid crystal separate out within the polymer structure. Liquidcrystal molecules within each droplet have localized order, but eachdroplet may be randomly aligned relative to other droplets in themixture. In some embodiments of switchable diffuser 136, the combinationof small droplet size and isotropic orientation of droplets in the PDLCmixture leads to a highly optically scattering structure in the absenceof a substantial electric field.

When a substantial electric field is applied across a PDLC typeswitchable diffuser 136, however, the orientation of the liquid crystaldroplets in the mixture changes, reduces the degree of opticalscattering that will occur when light is coupled into the structure andpasses out the other side. If a sufficient electrical field is appliedacross a PDLC type switchable diffuser 136, in accordance with one ormore embodiments of the present disclosure, the switchable diffuser 136structure will achieve a substantially transparent state such thatin-coupled light will pass through with little to no scattering.

Similarly, a PNLC type switchable diffuser 136, for example, may alsoprovide optically scattering/diffusion properties. A PNLC typeswitchable diffuser 136 comprises a network of polymer chains throughoutthe structure, where concentration of polymer within the within theliquid crystal may be about between 1% to 15%. Like PDLCs, PNLCs mayswitch between a substantially scattering state and a substantiallytransparent state under application of appropriate electric fields.

Switchable diffuser 136 may further comprise additional layers incombination with the scattering elements. Such additional layers mayprovide polarization stability, structural support, and electricconductivity in connection with the PDLC or PNLC materials.

Accordingly, switchable diffuser 136 can be controlled to assume one ofat least two different states—a diffuser/scattering state and atransparent state—depending on the electric field applied to it. Forpurposes of the present disclosure, the diffuser/scattering state mayalso be referred herein to as a “first state” or an “off state,” and thetransparent state may also be referred to herein as a “second state” oran “on state.”

As shown in FIG. 2, system 100 may include a controller 140 that isoperatively coupled with one or more of light sensor 122, light source132 and switchable diffuser 136. Controller 140 may be configured toactuate light source 132, causing light source 132 to project light.Controller 140 may further be configured to process image informationreceived by light sensor 122 during a time in which controller 140 hasactuated light source 132. Controller 140 may further be configured toselectively apply an electric field (e.g., a voltage) to the switchablediffuser 136 to achieve switching between an off state(diffusion/scattering state) and an on state (transparent state).Controller 140 may be configured to effectuate synchronized operation oflight sensor 122, light source 132, and switchable diffuser 136 toachieve a time division multiplexed propagation of flood light and dotlight projections.

In particular, controller 140 may be configured to selectively oscillatethe application of an electric field across switchable diffuser 136while light from light source 132 (which optionally will have passedthrough light projecting structure 134) is being in coupled at a firstsurface of the switchable diffuser 136 and out coupled through a secondsurface of switchable diffuser 136. Such selective oscillations causeswitchable diffuser 136 to switch between and off state and an on statesuch that during a first period of time the light emitted out of thesecond surface of switchable diffuser 136 comprises a flood lightprojection, and that during a second or subsequent period of time thelight emitted out of the second surface of switchable diffuser 136comprises a dot light projection.

The switchable diffuser 136 may be actuated in any manner and by anycombination of elements configured to control the application of anappropriate electric field. For example, with reference to FIG. 2,controller 140 may be coupled with a circuit including a voltage sourcethat may apply a voltage to switchable diffuser 136. Conductive elements142 and/or 144 may be integrated with or otherwise coupled to switchablediffuser 136 to enable an electric field to be applied across switchablediffuser 136. Controller 140 may selectively regulate the application ofvoltage from a voltage source to switchable diffuser 136 through thecircuitry connected thereto. In some embodiments, controller 140 mayactuate a switch that connects and/or disconnects a voltage source withone or more of conductive elements 142 and/or 144.

FIG. 3A illustrates a change in the operation of an example switchablediffuser 136 upon a change in an applied electric field across theswitchable diffuser caused by a switch from a first voltage condition toa second voltage condition, where the change between the first voltagecondition and second voltage condition (and consequently the “off” stateand the “on” state of the switchable diffuser 136) are controlled bycontroller 140 (not shown).

As shown, when a voltage source is controlled to deliver a first voltage(denoted by variable V₁ in the upper image of FIG. 3A) to a switchablediffuser 136 (identified as 136 a in the upper image), the switchablediffuser may remain in its natural condition and act as adiffuser/scatterer of incoming light. This may be referred to as the“off” state. In some embodiments, the first voltage, V₁, may be 0 V,wherein the “off” state actually corresponds to the voltage being turned“off” from the perspective of the switchable diffuser 136. It should beappreciated however, that the “off” state does not necessarily have tocorrespond to the voltage of a voltage source being turned off.

In some embodiments the “off” state of the switchable diffuser 136 maybe achieved where the first voltage is about between 0 V and 1 V. Inother embodiments, the “off” state of the switchable diffuser 136 may beachieved where the first voltage is any voltage that allows or causesthe liquid crystals within the polymeric structure of switchablediffuser to maintain or achieve a molecular arrangement or orientationthat causes in-coupled light to become substantially scattered as itpasses therethrough—thereby providing a flood light projection.

As shown, under the first voltage condition, light source 132 mayprovide light that is in-coupled to light projecting structure 134. Thelight projected from light projecting structure 134 may comprise aplurality of dot projections forming a dot array (i.e., a plurality ofnarrow beams of light projected in a structured or random pattern). Thedot projections are generally identified by numeral 135 in FIG. 3A. Thedot projections 135 may be incident upon a first surface of switchablediffuser 136, or otherwise coupled into switchable diffuser 136. Underthe first voltage condition, the dot projections 135 that are in coupledto switchable diffuser 136 are scattered by the molecular structure ofthe switchable diffuser 136. Consequently, switchable diffuser 136transforms the incoming structured light 135 received at a first surfaceinto flood light projected out of a second surface. The flood lightprojection out of the second surface of switchable diffuser 136 a isgenerally identified by numeral 137 in FIG. 3A.

Before discussing the lower image of FIG. 3A, it should be noted thatswitchable diffuser 136 is identified by numeral 136 a in the upperimage to designate the “off” state (or, in other words, adiffuser/scatterer condition), and is identified by numeral 136 b in thelower image to designate the “on” state (or, in other words, atransparent or substantially transparent condition). That is, switchablediffuser 136 a (shaded) and 136 b (not shaded) in FIG. 3A, are the sameswitchable diffuser, just in different operating states based on thedifferent electric field or voltage being applied (or not being applied,as the case may be), as between the first voltage condition and thesecond voltage condition.

As shown in the lower portion of FIG. 3A, when a voltage source iscontrolled to deliver a second voltage (denoted by variable V₂ in thelower image of FIG. 3A) to a switchable diffuser 136 (identified as 136b in the lower image), the molecular orientation of the switchablediffuser material may change such that the switchable diffuser istransparent or substantially transparent to the incoming light. This maybe referred to as the “on” state. In some embodiments, the secondvoltage, V₂, may be about between 1 V and 50 V, wherein the “on” stateactually corresponds to the voltage being turned “on” from theperspective of the switchable diffuser 136. It should be appreciatedhowever, that the “on” state does not necessarily have to correspond tothe voltage of a voltage source being turned on.

As noted above, it should be understood that the aforementioned “off”state does not necessarily have to correspond to the voltage of avoltage source being turned off, and that the “on” state does notnecessarily have to correspond to the voltage of a voltage source beingturned on. In some embodiments, the “on” state and the “off” state maybe said to assume the opposite states as those discussed above. That is,the first voltage condition may achieve an “on” state such that the dotprojections that are in coupled to switchable diffuser are allowed topass through substantially unscattered by the molecular structure of theswitchable diffuser, and the second voltage condition may achieve the“off” state such that the dot projections that are in coupled toswitchable diffuser are scattered/diffused by the molecular structure ofthe switchable diffuser and out coupled from the switchable diffuser asflood light. Consequently, switchable diffuser under the first voltagecondition (achieving the “on” state) may result in a dot arrayprojection therefrom, while switchable diffuser under the second voltagecondition (achieving the “off” state) may result in a flood projectiontherefrom.

In some embodiments, the switchable diffuser is substantiallytransparent to the in coupled dot projections in its natural state orunder a first voltage condition (e.g., where the applied voltage isabout between 0 V and 1 V) and substantially scattering/diffusive to thein coupled dot projections in its unnatural state or under a secondvoltage condition (e.g., where the applied voltage is about between 1 Vand 50 V). Either such scenario may be referred to as the “on” state orthe “off” state, depending on convention desired.

In some embodiments the “on” state of the switchable diffuser 136 may beachieved where the second voltage is 0 V. In other embodiments, the “on”state of the switchable diffuser 136 may be achieved where the firstvoltage is any voltage that allows or causes the liquid crystals withinthe polymeric structure of switchable diffuser to maintain or achieve amolecular arrangement or orientation that causes the switchable diffuserto be transparent or substantially transparent to incoming light, thusallowing the in-coupled light from light projecting structure 134 and/orlight source 132 to pass therethrough without substantial dispersion,diffusion, or other divergence that substantially disrupts the narrowbeam dot projection character of the light—thereby providing astructured or random pattern of dot beams to be projected onto a surfaceof an object and reflected back to a detector 120 (shown in FIGS. 1-2).

As shown in the lower image of FIG. 3A, under the second voltagecondition, light source 132 may continue to provide light that isin-coupled to light projecting structure 134. As above, the lightprojected from light projecting structure 134 continues to comprise aplurality of dot projections (i.e., a plurality of narrow beams of lightprojected in a structured or random pattern). The dot projections 135may be incident upon a first surface of switchable diffuser 136, orotherwise coupled into switchable diffuser 136. Under the second voltagecondition, the dot projections 135 that are in coupled to switchablediffuser 136 are not substantially scattered by the molecular structureof the switchable diffuser 136. Consequently, switchable diffuser 136allows the dot light beams 135 received at a first surface to passthrough and out of a second surface, continuing onward as narrow beamdot projections. The dot projections proceeding out of the secondsurface of switchable diffuser 136 b are generally identified by numeral138 in FIG. 3A.

Although FIG. 3A illustrates (by way of example only) that theswitchable diffuser 136 is positioned after the light projectingstructure 134 (e.g., projection lens), the switchable diffuser 136 mayalso be arranged in other positions with respect to the elements oflight projecting subsystem 130. For example, in some embodiments aswitchable diffuser may be positioned between the light source 132 andthe projection lens 134, as shown in FIG. 3B (with common numeralsrepresenting common elements discussed above with reference to FIG. 3A).In another example the light projection structure 134 and/or the lightsource 132 is made up of several elements, and the switchable diffusercan be positioned before, between or after any of them in thearrangement. For instance, where the light projecting subsystem 130includes a light engine (e.g., VCSEL) and a waveguide or diffractionelement (e.g., DOE), the switchable diffuser may be positioned before,between, or after any such elements.

For example, as shown in FIG. 3C, the light projecting subsystem 130 maycomprise a diffraction optical element (“DOE”) 139 to generate multipledots in combination with a VCSEL array 133, and the switchable diffuser136 may be positioned between them. Other examples are possible, and aperson of skill in the art will appreciate from the present disclosurethat any ordered arrangement including a switchable diffuser may bedeployed in implementations of the presently disclosed systems. In otherexamples, for instance, the light source 132 in FIG. 3A or FIG. 3B maycomprise the VCSEL array 133 a and DOE 133 b of FIG. 3C, and aswitchable diffuser may be positioned before, between, or after any suchelements. It will be understood that the configurations shown are merelyexamples provided for clarity of description, and that otherarrangements and variations may be implemented without exceeding thescope of the present disclosure.

Referring back now to FIGS. 1-2, controller 140 may cause operation ofthe aforementioned elements to be synchronized based on one or moredevice operating capabilities or requirements, environmental conditions,default or user defined settings, or any other input. For example, iflight sensor 122 is controlled to capture image information for a givenframe for a period of 1/60 seconds, the controller 140 may controlswitchable diffuser 136 to switch between an “off” state and an “on”state within the period of time that the image information is capturedfor a given frame. That is, for a given frame capture, controller 140may effectuate a switch of the switchable diffuser 136 such that bothdot projection reflections and flood projection reflections are received(in time-multiplexed manner, as noted above) by the detector 122 duringthe period of light capture for the frame. In some embodiments,controller 140 may be configured to oscillate the electric field appliedto the switchable diffuser at a rate that is between 2-100 times fasterthan the frame rate established for image capture. In some embodiments,controller 140 may be configured to oscillate the electric field appliedto the switchable diffuser at a rate that is between greater than 100times faster than the frame rate established for image capture.

FIG. 4 illustrates an example architecture depicting varioussubcomponents of controller 140 that may, upon execution, enable one ormore of the features disclosed herein in connection with one or moreother elements of system 100, including any one or more elements oflight projection subsystem 130 and detector 120. As shown, controller140 may be configured (or operatively coupled) with one or moreprocessing engines 150, and one or more machine readable instructions160 which, when executed by the one or more processing engines 150,cause one or more of the disclosed features to be effectuated. Machinereadable instructions 160 may be stored on a machine readable medium.The machine readable instructions 160 may have machine readable codecomprising an activation component 161, a field manipulation component162, synchronization component 163, dynamic adjustment component 164,and/or one or more other components 165.

Activation component 161 may be configured to detect when use of imagingsystem 100 is desired, and to correspondingly cause the system 100 toactivate one or more elements of light projection subsystem 130 and/ordetector 120. For example, if a user's mobile phone is equipped withsystem 100, and the user's input indicates a request for 3D facialrecognition (or other 3D topology mapping), activation component 161 mayidentify the indication provided by the user, and cause system 100 toactivate the light source 132 of light projection subsystem 130 and/ordetector subsystem 120. Activation component 161 may be furtherconfigured to determine an operation status of light projectionsubsystem 130 and/or detector subsystem 120. If the operation status oflight projection subsystem 130 and/or detector subsystem 120 issatisfactory, activation component 161 may activate field manipulationcomponent 162.

Field manipulation component 162 may be configured cause system 100 toapply an electric field to, adjust an electric field being applied to,or remove an electric field from a switchable diffuser 136 element oflight projection subsystem 130. For example, field manipulationcomponent 162 may cause controller 140 to apply, adjust or remove avoltage to/from switchable diffuser 136 from a voltage source to whichthe controller 140 is operatively coupled. By applying, adjusting orremoving such electric fields, field manipulation component 162 maycause switchable diffuser 136 two switch back-and-forth between an “off”state (diffusion/scattering state) and an “on” state (transparentstate). Field manipulation component 162 may be configured to time itsoperations in accordance with the operation of other elements of system100, for example, detector 120 and other components of controller 140.In so doing, field manipulation component 162 may draw on informationdetermined, stored, or otherwise provided by synchronization component163.

Synchronization component 163 may be configured to determine anoperation speed or rate of image capture being performed, or capable ofbeing performed, by detector subsystem 120 and/or controller 140 inconnection with detector subsystem 120. Additionally, synchronizationcomponent 163 may determine or control the timing of operation of suchelements, and informed field manipulation component 162 of the same. Forexample, as noted above, if light sensor 122 is controlled to captureimage information at 60 frames per second (meaning that for a givenframe image capture occurs for a period of 1/60 second or less),synchronization component 163 may identify this operation capacity(based on detection or based on pre-determined/stored information) andmay further provide a start and/or stop time to either or both ofactivation component 161 and field manipulation component 162. In otherwords, in some embodiments synchronization component 163 may beconfigured with a clock that can be used in connection with theoperations of activation component 161 and field manipulation component162 (or any other components of system 100), to synchronizefunctionality such that the desired performance may be achieved. Thedesired performance in a given situation may be pre-determined, or itmay be dynamically adjustable given one or more other detectableconditions. The dynamically adjustable features of the presentlydisclosed technology may be enabled, in whole or in part, by a dynamicadjustment component 164.

Dynamic adjustment component 164 may be configured to detect one or moreinternal or external conditions or requests that call for an adjustmentto any default or otherwise predetermined operation settings of system100. Dynamic adjustment component 164 may be informed by one or moresensors or detection engines operating in connection with one or moreother components 165. For example, a default setting of system 100 mayprovide that field manipulation component 162 will operate to switch theswitchable diffuser 136 between it “on” and “off” state such that,during image capture for an individual frame, the ratio of time forflood light 137 projection to time for dot projection 138 is 1:3. Thatis, during ¼ of the image capture time for a given frame, flood light137 is to be projected out of the second surface of switchable diffuser136, and during ¾ of the image capture time for a given frame, dotprojections 138 are to be projected out of the second surface ofswitchable diffuser 136. However, if dynamic adjustment component 164detects that ambient light conditions in the external environment ofsystem 100 provide poor illumination, dynamic adjustment component 164may determine that the ratio of time for floodlight 137 projection totime for dot projection 138 should be modified from 1:3 to 1:1 toprovide additional flood light 137 illumination on an object within thatenvironment (e.g., a user's face).

In the example above, dynamic adjustment component 164 may operate tocause field manipulation component 162 to impose a voltage oscillationpattern on switchable diffuser 136 such that switchable diffuser 136assumes and “on” state during approximately ½ of the image capture timefor an individual frame, and assumes an “off” state during the other ½of the image capture time for such frame. Consequently, during ½ of theimage capture time for a given frame, flood light 137 will be projectedout of the second surface of switchable diffuser 136, and during theother ½ of the image capture time for a given frame, dot projections 138will be projected out of the second surface of switchable diffuser 136.Thereby, field manipulation component 162 may operate responsively toone or more of dynamic adjustment component 164 and/or synchronizationcomponent 163, and/or activation component 161, and/or any othercomponents 165 of system 100.

In addition to external conditions, such as ambient light conditions,dynamic adjustment component 164 may be configured to detect when agiven situation calls for higher than default resolution and/or timingfor facial recognition. For example, if a user of a mobile phoneequipped with system 100 is simply trying to unlock their device usingfacial recognition, the default resolution may simply correspond to aratio of time for flood light 137 projection to time for dot projection138 of 1:3 (for each frame) and require that the image information becollected for 0.5 seconds at 60 frames per second. However, if a user isattempting to use the facial recognition capabilities of system 102login to a high-security or heavily restricted database, oralternatively if the user is attempting to use facial recognition toauthorize a purchase of an item for over $1000 USD, dynamic adjustmentcomponent 164 may determine that under such conditions a higherresolution facial rendering is required to achieve an adequate matchingcondition (e.g., with a stored template of the user's facial topology)to authorize the login or the purchase. Under such conditions, dynamicadjustment component 164 may be configured to cause field manipulationcomponent 162 and or synchronization component 163 to make necessaryadjustments so as to enable system 100 to generate or obtain higherresolution 3D information that satisfies the higher securityrequirements associated with the detected login request or purchaserequest. For example, dynamic adjustment component 164 may require fieldmanipulation component 162 to provide more or less floodlight ascompared to dot projections for a first period of image capture, andthen to cause an adjustment to such floodlight and dot projectionproportions for a second period of image capture. Additionally oralternatively, dynamic adjustment component 164 may require that fieldmanipulation component operate for a longer period of time thanotherwise set by default. Similarly, dynamic adjustment component 164may cause activation component 161 and synchronization component 163 tooperate for a longer period of time than otherwise set by default forcircumstances where higher security is demanded, and consequentlyhigh-resolution image information is required. Any and all of suchsettings and dynamic adjustments may be preset or predefined by a user,or may be learned over time with repetitive use and training of system100 in various circumstances.

As noted previously, the controller 140 may control switchable diffuser136 to switch between an “off” state and an “on” state within the periodof time that the image information is captured for a given frame. It isalso noted here that controller 140 (e.g., via field manipulationcomponent 162) may cause switchable diffuser 136 to switch between anoff state and an on state multiple times during image capture for agiven frame. That is, for a given frame capture, controller 140 mayeffectuate a switch of the switchable diffuser 136 such that both dotprojection reflections and flood projection reflections are received (intime-division multiplexed manner, as noted above) by the detector 122during the period of light capture for the frame. In some embodiments,controller 140 may be configured to oscillate the electric field appliedto the switchable diffuser at a rate that is between 2-100 times fasterthan the frame rate established for image capture. In some embodiments,controller 140 may be configured to oscillate the electric field appliedto the switchable diffuser at a rate that is between greater than 100times faster than the frame rate established for image capture.

Synchronization component 163 may operate to inform other elements ofsystem 100 as to the timing of light projections, thereby informing theprocessing of light information received by the light sensor 122 ofdetector subsystem 120 such that system 100 may discriminate orotherwise distinguish between light information that is associated withreflected floodlight, and light information that is associated withreflected dot projections, and adjust other operations accordingly. Inother words, synchronization component 163 may provide multiplexingfunctionality in connection with received image information. Thus, forexample, synchronization component 163 may enable detector 120 tocapture IR image photos (e.g., heat signature photos) during timeperiods of flood light projection, and IR dot array photos during IR dotprojections.

As will be appreciated by those of skill in the art, although shown inFIG. 4 as being embodied as machine-readable instructions 160, any oneor more of activation component 161, field manipulation component 162,synchronization component 163, dynamic adjustment component 164, and/orother components 165 may be implemented in either hardware or softwareor both.

FIG. 5 illustrates a system 500 that may be implemented in accordancewith one or more embodiments of the present disclosure. System 500 isdepicted as a variation of system 100, where module 110 is equipped withboth a non-ToF light detector (e.g., detector 120, discussed above), aswell as a Time of Flight detector, ToF detector 170. Detector 120 maycapture/transduce/filter reflections of light (structured light and/orflood light) off of the surface(s) an object(s) upon which the light isprojected (e.g., a face). Light information captured by detector 120 maybe used to determine depth information (in the case of reflectedcolumnated light, based on shifts and distortions relative to areference) and object feature information (in the case of reflectedflood light, based on wavelength/frequency). The ToF detector 170, onthe other hand, operates based on the pulsed time-of-flight principle(rather than being primarily based on shifts, distortion, frequency, orwavelength).

The pulsed time-of-flight principle recognizes that the time light needsto travel from a light source to an object and back to a detectorchanges depending on how far away the object is from the light sourceand/or ToF detector—i.e., the further the distance the light has totravel through space, the longer amount of time it will take for thelight to reach the ToF detector. For ToF detection to operate properly,both the light source and the ToF detector must be synchronized suchthat distances can be extracted and calculated from the time differencesdetected. In particular, the timing details of the light pulse generatedby the light source and the timing details of the light received back atthe ToF detector should be tightly controlled and/or monitored. Theresolution of ToF based images enhances with enhanced monitoring and/orcontrol of timing.

In the embodiment shown in FIG. 5, module 110 is provided with both anon-ToF detector 120 as well as a ToF detector 170. Both are configuredto receive light reflections from the light projected from lightprojection system 130, but each assesses the light differently (orproduce signals that may be assessed differently) to derive depthinformation and/or other structural features about objects upon whichthe light projected from light projecting system 130 is incident.

In some embodiments, light projecting subsystem 130 of system 500 mayinclude a single light source and a switchable diffuser 136. Such lightsource and switchable diffuser 136 may operate in accordance with one ormore features of such elements as discussed herein with reference toFIGS. 1-4. Moreover, with reference to FIG. 5, in some embodimentscontroller 140 may be configured to operate only one of detector 120 andToF detector 170 during a given image capture period—e.g., in “ToF mode”or “non-ToF mode” (ToF mode referring to the situation where only ToFdetector 170 is operating during a given image capture period, and“non-ToF mode” referring to the situation where only detector 120 isoperating during a given image capture period (e.g. in accordance withFIGS. 1-4).

In other embodiments, controller 140 may be configured to operate bothdetector 120 and ToF detector 170 together during a given image captureperiod—e.g., in “hybrid mode” (hybrid mode referring to the case wherecontroller 140 synchronizes operations of detector 120, ToF detector 170(along with other elements of system 500, e.g., light projectingsubsystem 130) such that both detectors are in operation during a givenimage capture period.

In some embodiments, controller 140 may effectuate operation of system500 in ToF mode, non-ToF mode, or hybrid mode based on input from a user(e.g., user selection). In some embodiments, controller 140 may beconfigured to effectuate a switch between modes depending on one or moredetected condition(s), e.g., lighting conditions, component statusdetection, etc. For instance, if dynamic adjustment component 164 ofcontroller 140 detects that ambient light conditions in the externalenvironment of system 100 provide poor illumination (e.g., anillumination that falls beneath a predefined threshold (e.g. a luminancethreshold)), or another element of system 500 (including any element ofsystem 100) detects that the object being imaged is too far away forstructured light detection to be effective (e.g., an object is beyond apredefined distance (e.g., beyond 2 meters), dynamic adjustmentcomponent 164 may determine that ToF imaging will generate a higherresolution image than the image generated via detector 120. In responseto such a determination, controller 140 may effectuate operation of thesystem such that module 110 operates in ToF mode.

In another example, if an element of system 500 (including any elementof system 100) detects that the object being imaged is within apredetermined distance from the detector within which the structuredlight detection via detector 120 will generate an image with a higherresolution that is superior to that provided by ToF detection (e.g., anobject is within a predefined distance (e.g., within 1 meter), thendynamic adjustment component 164 may determine that detector 120 willgenerate a higher resolution image than the image generated via ToFdetector 170. In response to such a determination, controller 140 mayeffectuate operation of the system such that module 110 operates innon-ToF mode.

In still another example, if an element of system 500 (including anyelement of system 100) detects some condition(s) that make ToF detectionvia detector 170 desired (or undesired as the case may be) and/or somecondition(s) that make structured light detection via detector 120desired (or undesired as the case may be), then dynamic adjustmentcomponent 164 may determine that the best image information may beobtained by operating detector 120 and ToF detector 170 in concert(e.g., simultaneously, or in a time-multiplexed manner) during a givenimage capture period. In response to such a determination, controller140 may effectuate operation of the system such that module 110 operatesin hybrid mode. Such a determination may be made based on predeterminedrules/criteria with regard to such detected conditions, as may be setfor a given application.

In hybrid mode operation, controller 140 may regulate and/or monitor thetiming of switchable diffuser's switch between states (and therebymonitor the switching between flood light projections and structuredarray light projections), and treat one or the other as the “pulse” totrack for purposes of computing time-of-flight differences in connectionwith light received at the ToF detector 170. That is, controller 140—viasynchronization component 163 or another component—may synchronizeoperation of detector 120 and ToF detector 170 with the timing of thedifferent light projections (e.g., structured dot array projections,flood light projections, etc.) propagating from light projectionsubsystem 130. In this way, the time-multiplexed light informationobtained via detector 120 and ToF detector 170 may be coherentlyde-multiplexed and/or otherwise resolved by system 500. In someembodiments, the imaging information obtained via detector 120 and ToFdetector 170 during hybrid mode operation may be combined to generate acomposite image.

In still further embodiments, hybrid mode operations may tuned tooptimize resolution (or enhance resolution) based on the one or moreconditions detected. For example, if dynamic adjustment component 164 ofcontroller 140 detects that ambient light conditions in the externalenvironment of system 500 provide an illumination quality that makehybrid mode desired, but illumination should be enhanced by flood lightin a proportion greater than a 1:1 (flood light projection to structuredarray projection ratio), dynamic adjustment component 164 may determinenot only that hybrid mode should be activated/selected, but further thatthe ratio of time for floodlight projections to time for structured dotprojections should be modified from 1:1 to 2:1 to provide additionalflood light illumination on an object within that environment (e.g., auser's face).

Alone or in conjunction with dynamic adjustment component 164,synchronization component 163 may be configured to make correspondingadjustments to aid controller 140 in resolving the light information astransduced by detector 120 and ToF detector 170 during hybrid mode. Forexample, synchronization component 163 may determine an operation speedor rate of image capture set to be performed by detector subsystem 120,ToF detector 170 and/or controller 140, and may facilitate control ofthe timing of operation or initialization of such elements.Synchronization component 163 and/or dynamic adjustment component 164may inform field manipulation component 162 of the same. For example, asnoted above, if light sensor 122 is controlled to capture imageinformation at 60 frames per second (meaning that for a given frameimage capture occurs for a period of 1/60 second or less),synchronization component 163 may identify this operation capacity(based on detection or based on pre-determined/stored information) andmay further provide a start and/or stop time to either or both ofactivation component 161 and field manipulation component 162. In otherwords, in some embodiments synchronization component 163 may beconfigured with a clock that can be used in connection with theoperations of activation component 161, field manipulation component162, dynamic adjustment component 163 (or any other components of system500), to synchronize functionality such that the desired performance maybe achieved in a given scenario. The desired performance in a givensituation may be pre-determined, or it may be dynamically adjustable, inwhole or in part, by a dynamic adjustment component 164 based on one ormore detectable conditions.

Synchronization component 163 may, in hybrid mode, operate to informother elements of system 500 as to the timing of light projections,thereby informing the processing of light information received bydetector subsystem 120 and ToF detector 170 such that system 500 may notonly discriminate or otherwise distinguish between light informationthat is associated with reflected floodlight, and light information thatis associated with reflected dot projections, but also may distinguishlight information associated with ToF derivations from light informationassociated with non-ToF derivations, and adjust other operationsaccordingly. In other words, synchronization component 163 may providemultiplexing functionality in connection with received imageinformation. Thus, for example, synchronization component 163 may enabledetector 120 to capture IR image photos (e.g., heat signature photos)during time periods of flood light projection, and IR dot array photosduring IR dot projections, and in the same image capture period enableToF detector 170 to capture temporally resolved image photos during timeperiods of IR dot projections (e.g., or other structured arrayprojections), leveraging the structured light bursts as the “pulses” oflight in accordance with the pulsed time-of-flight principal.

Said differently, synchronization component 163 may be configured tosynchronize or otherwise coordinate the ToF detector 170's image capturewith detector 120's (e.g., IR detector) image capture, and furthersynchronize both with the switchable diffuser 136's switches between“off” and “on” states. In some such embodiments, switchable diffuser 136may be controlled to output short pulsed of flood light (e.g., 1-100 ns)or long pulsed dot light (e.g., 100 μs-30 ms) based on a switch in theapplied voltage. The ToF detector 170 may be controlled by controller140 to be pulsed to provide pulsed amplitude modulation, pulsedfrequency modulation, and/or continuous wave AM/FM. In some embodiments,the ToF detector 170 and the structured light detector 120 (e.g., IRdetector) may be controlled by controller 140 such that they aresynchronized to match or otherwise operate in alignment with thetime-division multiplexed light (flood light and structured light beingtime multiplexed together) signals generated by the switchable diffuser.

Persons of ordinary skill in the art will appreciate that all of theelements of controller 140 as discussed with reference to FIGS. 1-4 maybe extended to embodiments employing ToF detector 170, including asdiscussed above with respect to synchronization component 163 anddynamic adjustment component 164. As such, system embodiments inaccordance with system 500, or variations thereof, may enable thecapture of 3D ToF photos/image information in synchronization with 2D IRdot photos/image information.

In embodiments utilizing ToF detectors in combination with theswitchable diffuser and other light detectors, the systems of thepresent disclosure may provide enhance security features to ensure, forexample, that the object being imaged is the true 3D object and not a 2Drendition of the object used to spoof the system. In some embodiments,the ToF detector may be controlled by controller 140 to be continuouslyor periodically calibrated.

FIG. 6 illustrates a process flow diagram depicting a method that may beimplemented in accordance with one or more embodiments of the presentdisclosure. As shown, at operation 202 method 200 comprises receivinglight generated by a light source light and responsively projecting aplurality of collimated beams of light. At operation 204 method 200comprises: providing a switchable diffuser having a first surface and asecond surface, the switchable diffuser coupled to a voltage source andconfigured to change from a first state to a second state responsive tothe voltage source being changed from a first voltage condition to asecond voltage condition. At operation 206 method 200 comprises:oscillating the voltage source between the first voltage condition andthe second voltage condition in accordance with a predeterminedoscillation pattern, the voltage oscillations causing alternating floodlight and dot array projections to be emitted from the second surface ofthe switchable diffuser in a time-division multiplexed manner. Atoperation 208 method 200 comprises: detecting, at a light sensor, lightinformation from the alternating flood light and dot array lightreflections off of an object, wherein the light sensor is synchronizedwith the voltage oscillations and/or the alternations in flood light anddot array light projection. At operation 210 method 200 comprises:demultiplexing light information detected at the light sensor. Atoperation 212 method 200 comprises: generating a 3D map of the objectbased on the demultiplexed light information.

The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and sub-combinations are intended to fall withinthe scope of this disclosure. In addition, certain method or processblocks may be omitted in some implementations. The methods and processesdescribed herein are also not limited to any particular sequence, andthe blocks or states relating thereto can be performed in othersequences that are appropriate. For example, described blocks or statesmay be performed in an order other than that specifically disclosed, ormultiple blocks or states may be combined in a single block or state.The exemplary blocks or states may be performed in serial, in parallel,or in some other manner. Blocks or states may be added to or removedfrom the disclosed exemplary embodiments. The exemplary systems andcomponents described herein may be configured differently thandescribed. For example, elements may be added to, removed from, orrearranged compared to the disclosed exemplary embodiments.

Throughout this specification, plural instances may implementcomponents, operations, or structures described as a single instance.Although individual operations of one or more methods are illustratedand described as separate operations, one or more of the individualoperations may be performed concurrently, and nothing requires that theoperations be performed in the order illustrated. Structures andfunctionality presented as separate components in exemplaryconfigurations may be implemented as a combined structure or component.Similarly, structures and functionality presented as a single componentmay be implemented as separate components. These and other variations,modifications, additions, and improvements fall within the scope of thesubject matter herein.

Although an overview of the subject matter has been described withreference to specific exemplary embodiments, various modifications andchanges may be made to these embodiments without departing from thebroader scope of embodiments of the present disclosure. Such embodimentsof the subject matter may be referred to herein, individually orcollectively, by the term “invention” merely for convenience and withoutintending to voluntarily limit the scope of this application to anysingle disclosure or concept if more than one is, in fact, disclosed.

The embodiments illustrated herein are described in sufficient detail toenable those skilled in the art to practice the teachings disclosed.Other embodiments may be used and derived therefrom, such thatstructural and logical substitutions and changes may be made withoutdeparting from the scope of this disclosure. The Detailed Description,therefore, is not to be taken in a limiting sense, and the scope ofvarious embodiments is defined only by the appended claims, along withthe full range of equivalents to which such claims are entitled.

As used herein, the term “or” may be construed in either an inclusive orexclusive sense. Moreover, plural instances may be provided forresources, operations, or structures described herein as a singleinstance. Additionally, boundaries between various resources,operations, engines, and data stores are somewhat arbitrary, andparticular operations are illustrated in a context of specificillustrative configurations. Other allocations of functionality areenvisioned and may fall within a scope of various embodiments of thepresent disclosure. In general, structures and functionality presentedas separate resources in the exemplary configurations may be implementedas a combined structure or resource. Similarly, structures andfunctionality presented as a single resource may be implemented asseparate resources. These and other variations, modifications,additions, and improvements fall within a scope of embodiments of thepresent disclosure as represented by the appended claims. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

What is claimed is:
 1. A system, comprising: a light projecting systemconfigured to project a plurality of collimated beams of light; anstructured light sensor; a Time-of-Flight (ToF) sensor; a switchablediffuser having a first surface and a second surface, the switchablediffuser coupled to a control source and configured to change from afirst state to a second state responsive to the control source beingchanged from a first condition to a second condition; wherein in thefirst state the switchable diffuser is configured to receive collimatedbeams of light at the first surface and project a flood light out of thesecond surface; wherein in the second state the switchable diffuser isconfigured to receive collimated beams of light at the first surface andproject collimated beams of light out of the second surface; and aprocessing engine electrically coupled with a non-transitory computerreadable medium having machine readable instructions stored thereon,which, when executed by the processing engine, cause the system to:oscillate, during, a first image capture period, the control sourcebetween the first condition and the second condition in accordance witha first predetermined pattern, wherein the first predetermined patterncomprises switching between the first condition and the second conditiontwo or more times to achieve a first predetermined ratio of flood lightprojection to collimated light projection; oscillate, during a secondimage capture period, the control source between the first condition andthe second condition in accordance with a second predetermined pattern,wherein the second predetermined pattern comprises switching between thefirst condition and the second condition two or more times to achieve asecond predetermined ratio of flood light projection to collimated lightprojection, and further wherein the second predetermined ratio isdifferent than the first predetermined ratio; wherein the ToF sensor andthe structured light sensor are configured to receive reflections ofcollimated light from one or more of the same pulses of collimated lightduring a single image capture period.
 2. The system of claim 1, wherein:the light projecting system comprises a waveguide, the waveguidecomprising a surface A and a surface B; the surface A comprises aplurality of grating structures; the waveguide is configured to guide anin-coupled light beam to undergo total internal reflection between thesurface A and the surface B; and the grating structures are configuredto disrupt the total internal reflection to cause at least a portion ofthe in-coupled light beam to couple out of the waveguide from thesurface A, the portion of the in-coupled light beam coupled out of thewaveguide forming out-coupled light beams comprising the plurality ofcollimated beams of light.
 3. The system of claim 2, wherein: thesurface A is in an x-y plane comprising an x-direction and a y-directionperpendicular to each other; the in-coupled light beam propagates insidethe waveguide substantially along the x-direction of the x-y plane; theout-coupled light beams propagate substantially along a z-directionnormal to the x-y plane; the grating structure is each associated with agrating depth, a duty cycle, a period, and an orientation in the x-yplane with respect to the z-direction; the grating structures atdifferent x-direction positions have at least one of different gratingdepths or different grating duty cycles; the grating structures atdifferent x-direction positions have different periods; and the gratingstructures at different y-direction positions have differentorientations.
 4. The system of claim 1, wherein the light projectingsystem comprises a plurality of diodes.
 5. The system of claim 1,wherein the switchable diffuser comprises a polymer-liquid crystalmixture having a molecular orientation responsive to an applied voltage.6. The system of claim 1, wherein the switchable diffuser comprises apolymer dispersed liquid crystal.
 7. The system of claim 1, wherein theswitchable diffuser comprises a polymer network liquid crystal.
 8. Thesystem of claim 1, wherein the first predetermined pattern causes thelight projecting out of the second surface of the switchable diffuser tocomprise alternating pulses of flood light and collimated beams of lightachieving a time division multiplexed emission.
 9. The system of claim1, wherein the first condition is an applied voltage of 0V, and thesecond voltage condition is an applied voltage of between 1 V and 50 V.10. The system of claim 1, wherein the non-transitory computer readablemedium is further configured with machine readable instructions storedthereon, which, when executed by the processing engine, cause the systemto: adjust the time period of one or more of the first image captureperiod and the second image capture period based on one or more of adetected ambient lighting condition and a transaction securitycondition.
 11. The system of claim 1, wherein the first predeterminedpattern is an oscillation pattern configured to achieve a predeterminedprojection ratio of flood light to collimated light.
 12. The system ofclaim 1, wherein the first predetermined pattern is an oscillationpattern configured to achieve a predetermined projection ratio of floodlight to collimated light, and further wherein the projection ratio is1:1.
 13. The system of claim 1, wherein the first predetermined patternis an oscillation pattern configured to achieve a predeterminedprojection ratio of flood light to collimated light, and further whereinthe projection ratio is 10:1.
 14. The system of claim 1, wherein thefirst predetermined pattern is an oscillation pattern configured toachieve a predetermined projection ratio of flood light projection timeto collimated light projection time, and further wherein the projectionratio is about between 1:1 to 10:1.
 15. The system of claim 1, whereinthe collimated beams of light comprise infrared frequency light.
 16. Alight projecting system, comprising: an IR detector configured tocapture light information based on one or more flood light reflectionsoff of an object, and array reflections off of an object; aTime-of-Flight (ToF) detector configured to detect differences betweenparticles based on their time of flight; a switchable diffuser having afirst surface and a second surface, the switchable diffuser coupled to acontrol source and configured to change from a first state to a secondstate responsive to the control source being changed from a firstcondition to a second condition; wherein in the first state theswitchable diffuser is configured to receive at least a portion of theplurality of collimated beams of light at the first surface and projecta flood light out of the second surface; wherein in the second state theswitchable diffuser is configured to permit at least a portion of theplurality of collimated beams of light to propagate out of the secondsurface as an array; and a processing engine electrically coupled with anon-transitory computer readable medium having machine readableinstructions stored thereon, which, when executed by the processingengine, cause the system to: oscillate, during a first image captureperiod, the control source between the first condition and the secondcondition in accordance with a first predetermined pattern, wherein thefirst predetermined pattern comprises switching between the firstcondition and the second condition two or more times to achieve a firstpredetermined ratio of flood light projection to collimated lightprojection; oscillate, during a second image capture period, the controlsource between the first condition and the second condition inaccordance with a second predetermined pattern, wherein the secondpredetermined pattern comprises switching between the first conditionand the second condition two or more times to achieve a secondpredetermined ratio of flood light projection to collimated lightprojection, and further wherein the second predetermined ratio isdifferent than the first predetermined ratio; and cause the switchablediffuser to emit pulses of collimated beams of light to effectuate amodulation of the collimated beams of light that the ToF detector isconfigured to resolve.
 17. The light projecting system of claim 16,wherein: the modulation is one or more of pulsed amplitude modulation,pulsed frequency modulation, continuous wave amplitude modulation, andcontinuous wave frequency modulation.
 18. The light projecting system ofclaim 16, further comprising a waveguide, wherein: the waveguidecomprises a surface A and a surface B; the surface A comprises aplurality of grating structures; the waveguide is configured to guide anin-coupled light beam to undergo total internal reflection between thesurface A and the surface B; and the grating structures are configuredto disrupt the total internal reflection to cause at least a portion ofthe in-coupled light beam to couple out of the waveguide from thesurface A, the portion of the in-coupled light beam coupled out of thewaveguide forming out-coupled light beams comprising the plurality ofcollimated beams of light.
 19. The light projecting system of claim 18,wherein: the surface A is in an x-y plane comprising an x-direction anda y-direction perpendicular to each other; the in-coupled light beampropagates inside the waveguide substantially along the x-direction ofthe x-y plane; the out-coupled light beams propagate substantially alonga z-direction normal to the x-y plane; the grating structure is eachassociated with a grating depth, a duty cycle, a period, and anorientation in the x-y plane with respect to the z-direction; thegrating structures at different x-direction positions have at least oneof different grating depths or different grating duty cycles; thegrating structures at different x-direction positions have differentperiods; and the grating structures at different y-direction positionshave different orientations.
 20. The light projecting system of claim16, further comprising a plurality of diodes.
 21. The light projectingsystem of claim 16, wherein the collimated beams of light compriseinfrared frequency light.
 22. A light projecting method, comprising:receiving light generated by a light source light and responsivelyprojecting a plurality collimated beams of light; providing a switchablediffuser having a first surface and a second surface, the switchablediffuser coupled to a voltage source and configured to change from afirst state to a second state responsive to the voltage source beingchanged from a first condition to a second condition; and oscillating,during a first image capture period, the voltage source between thefirst condition and the second condition in accordance with a firstpredetermined pattern, the voltage oscillations causing alternatingflood light and dot array projections to be emitted from the secondsurface of the switchable diffuser in a time-division multiplexedmanner; wherein the first predetermined pattern comprises switchingbetween the first condition and the second condition two or more timesto achieve a first predetermined ratio of flood light projection to dotarray projection; and oscillating, during a second image capture period,the control source between the first condition and the second conditionin accordance with a second predetermined pattern, wherein the secondpredetermined pattern comprises switching between the first conditionand the second condition two or more times to achieve a secondpredetermined ratio of flood light projection to dot array projection,and further wherein the second predetermined ratio is different than thefirst predetermined ratio; detecting, at a Time-of-Flight (ToF) sensor,light information from the alternating flood light and dot array lightreflections off of an object, wherein the light sensor is synchronizedwith the voltage oscillations and/or the alternations in flood light anddot array light projection; demultiplexing light information detected atthe light sensor; and generating a 3D map of the object based on thedemultiplexed light information.
 23. The method of claim 22, wherein:projecting a plurality of collimated beams of light comprises projectinga plurality of collimated beams of light from a waveguide, the waveguidecomprising a surface A and a surface B; the surface A comprises aplurality of grating structures; the waveguide is configured to guide anin-coupled light beam to undergo total internal reflection between thesurface A and the surface B; and the grating structures are configuredto disrupt the total internal reflection to cause at least a portion ofthe in-coupled light beam to couple out of the waveguide from thesurface A, the portion of the in-coupled light beam coupled out of thewaveguide forming out-coupled light beams comprising the plurality ofcollimated beams of light.
 24. The method of claim 22, wherein: thesurface A is in an x-y plane comprising an x-direction and a y-directionperpendicular to each other; the in-coupled light beam propagates insidethe waveguide substantially along the x-direction of the x-y plane; theout-coupled light beams propagate substantially along a z-directionnormal to the x-y plane; the grating structure is each associated with agrating depth, a duty cycle, a period, and an orientation in the x-yplane with respect to the z-direction; the grating structures atdifferent x-direction positions have at least one of different gratingdepths or different grating duty cycles; the grating structures atdifferent x-direction positions have different periods; and the gratingstructures at different y-direction positions have differentorientations.
 25. The method of claim 22, wherein the firstpredetermined pattern causes the light projecting out of the secondsurface of the switchable diffuser to comprise alternating pulses offlood light and collimated beams of light achieving a time divisionmultiplexed emission.
 26. The method of claim 22, wherein the firstcondition is an applied voltage of 0V, and the second voltage conditionis an applied voltage of between 1 V and 50 V.
 27. The method of claim22, wherein the first predetermined pattern comprises switching betweenthe first condition and the second condition two or more times during afirst image capture period to achieve a first predetermined ratio offlood light projection to collimated light projection.